Increased peak & trough plasma conc of digoxin. May increase risk of hyperkalemia w/ other medicinal products that may provoke hyperkalemia eg, salt substitutes containing K, K-sparing diuretics, ACE inhibitors, AIIA, NSAIDs (including selective COX-2 inhibitors), heparin, immunosuppressives (cyclosporin or tacrolimus) & trimethoprim. Attenuated diuretic-induced K loss w/ K-sparing diuretics (eg, spirinolactone, eplerenone, triamterene or amiloride), K supplements or K-containing salt substitutes. Increased serum conc & toxicity of lithium. Antihypertensive effect may be reduced w/ NSAIDs (ie, ASA at anti-inflammatory dose, COX-2 inhibitors & non-selective NSAIDs). May result in vol depletion w/ furosemide & hydrochlorothiazide. Increased BP-lowering effect w/ other antihypertensives. Higher frequency of adverse events in dual blockade of the RAAS through combination w/ ACE inhibitors or aliskiren. Hypotensive effects may be potentiated w/ baclofen, amifostine. May aggravate orthostatic hypotension w/ alcohol, barbiturates, narcotics or antidepressants. Reduced antihypertensive effects w/ systemic corticosteroids.